What is pulmonary surfactant

Pulmonary surfactant is a complex and highly surface active material composed of lipids and proteins which is found in the fluid lining the alveolar surface of the lungs. Surfactant prevents alveolar collapse at low lung volume, what is pulmonary surfactant, and preserves bronchiolar patency during normal and forced respiration biophysical functions.

Surfactant is an agent that decreases the surface tension between two media. The surface tension between gaseous-aqueous interphase in the lungs is decreased by the presence of a thin layer of fluid known as pulmonary surfactant. It is essential for efficient exchange of gases and for maintaining the structural integrity of alveoli. Surfactant is a secretory product, composed of lipids and proteins. The lipid and protein components are synthesized separately and are packaged into the lamellar bodies in the AT-II cells.

What is pulmonary surfactant

Pulmonary surfactant is a surface-active complex of phospholipids and proteins formed by type II alveolar cells. By adsorbing to the air-water interface of alveoli , with hydrophilic head groups in the water and the hydrophobic tails facing towards the air, the main lipid component of surfactant, dipalmitoylphosphatidylcholine DPPC , reduces surface tension. As a medication, pulmonary surfactant is on the WHO Model List of Essential Medicines , the most important medications needed in a basic health system. Alveoli can be compared to gas in water, as the alveoli are wet and surround a central air space. The surface tension acts at the air-water interface and tends to make the bubble smaller by decreasing the surface area of the interface. Compliance is the ability of lungs and thorax to expand. Lung compliance is defined as the volume change per unit of pressure change across the lung. This difference in inflation and deflation volumes at a given pressure is called hysteresis and is due to the air-water surface tension that occurs at the beginning of inflation. However, surfactant decreases the alveolar surface tension , as seen in cases of premature infants with infant respiratory distress syndrome. Pulmonary surfactant thus greatly reduces surface tension , increasing compliance allowing the lung to inflate much more easily, thereby reducing the work of breathing. It reduces the pressure difference needed to allow the lung to inflate.

However, surfactant decreases what is pulmonary surfactant alveolar surface tensionas seen in cases of premature infants with infant respiratory distress syndrome. The lipid and protein components are synthesized separately and are packaged into the lamellar bodies in the AT-II cells.

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Federal government websites often end in. The site is secure. Pulmonary surfactant is essential for life as it lines the alveoli to lower surface tension, thereby preventing atelectasis during breathing. The hydrophobic proteins, SP-B and SP-C, together with dipalmitoylphosphatidylcholine, confer surface tension—lowering properties to the material. The more hydrophilic surfactant components, SP-A and SP-D, participate in pulmonary host defense and modify immune responses. Specifically, SP-A and SP-D bind and partake in the clearance of a variety of bacterial, fungal, and viral pathogens and can dampen antigen-induced immune function of effector cells. Emerging data also show immunosuppressive actions of some surfactant-associated lipids, such as phosphatidylglycerol. Conversely, microbial pathogens in preclinical models impair surfactant synthesis and secretion, and microbial proteinases degrade surfactant-associated proteins.

What is pulmonary surfactant

Federal government websites often end in. Before sharing sensitive information, make sure you're on a federal government site. The site is secure. NCBI Bookshelf. Hina Khawar ; Komal Marwaha. Authors Hina Khawar ; Komal Marwaha 1. Pulmonary surfactant is a lipoprotein complex that lines the alveoli and decreases the surface tension to prevent lung atelectasis.

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This difference in inflation and deflation volumes at a given pressure is called hysteresis and is due to the air-water surface tension that occurs at the beginning of inflation. Retrieved Archived from the original on Ex-situ measurements of surface tension and interfacial rheology can help to understand the functionality of pulmonary surfactants. Main article: Pulmonary surfactant medication. However the significance of his discovery was not understood by the scientific and medical community at that time. Comparative Biochemistry and Physiology. A pathophysiological role for surfactant was first appreciated in premature infants with respiratory distress syndrome and hyaline membrane disease, a condition which is nowadays routinely treated with exogenous surfactant replacement. Read Edit View history. Tools Tools.

Pulmonary surfactant is a complex and highly surface active material composed of lipids and proteins which is found in the fluid lining the alveolar surface of the lungs. Surfactant prevents alveolar collapse at low lung volume, and preserves bronchiolar patency during normal and forced respiration biophysical functions. In addition, it is involved in the protection of the lungs from injuries and infections caused by inhaled particles and micro-organisms immunological, non-biophysical functions.

PMID Comparative Biochemistry and Physiology A. OCLC Toggle limited content width. This difference in inflation and deflation volumes at a given pressure is called hysteresis and is due to the air-water surface tension that occurs at the beginning of inflation. The apolipoproteins are produced by the secretory pathway in type II cells. Pulmonary surfactant thus greatly reduces surface tension , increasing compliance allowing the lung to inflate much more easily, thereby reducing the work of breathing. The lipid-protein interaction is very important for the structural organization of surfactant monolayer and its functioning. S2CID Comparative Biochemistry and Physiology. Thus, the surfactant density at the air water interface remains high and is relatively preserved throughout expiration, decreasing the surface tension even further. Tools Tools. Gov't Review. Wheater's functional histology : a text and colour atlas. For some pulmonary conditions surfactant replacement therapy is on the horizon, but for the majority much more needs to be learnt about the pathophysiological role the observed surfactant abnormalities may have.